Recently, a small base station for a home and a small office referred to as a home node B (HNB) has been under study in a 3GPP (3rd Generation Partnership Project).
An operator sets a CSG ID (Closed Subscriber Group Identity) of a closed subscriber group (Closed Subscriber Group, hereinafter abbreviated as a “CSG”) in a HNB in order to limit access to the HNB. The HNB allows access only from a user equipment (UE: User Equipment such as a mobile station or a terminal) whose allowed list (allowed Closed Subscriber Group identifies subscribers list, hereinafter abbreviated as an “allowed CSG list”) includes the CSG ID of the HNB, and limits access from other UEs.
The HNB includes the following (1) to (3) access modes. The UE from which the HNB allows access differs according to the access mode. The HNB can perform preferential control according to the UE which has accessed (Non-patent Document 1). As an example of the preferential control, there can be pointed out allowing preferential access (such as preferential bandwidth assignment, securement of a resource for access of the UE having the allowed CSG list including the CSG ID of the HNB even if the number of UEs which have made simultaneous accesses has increased and contention has occurred), assignment of a special charging rate, or the like, for the UE whose allowed CSG list includes the CSG ID of the HNB.
(1) Close Mode
The HNB allows access only from the UE whose allowed CSG list includes the CSG ID of the HNB.
(2) Open Mode
The HNB does not limit access
(3) Hybrid Mode
The HNB allows access from the UE whose allowed CSG list includes the CSG ID of the HNB and other usual UEs whose allowed CSG lists do not include the CSG ID of the HNB. The hybrid mode enables the HNB to perform the preferential control over the UE whose allowed CSG list includes the CSG ID of the HNB.    [Non-patent Document 1] 3GPP TS 22.220 V10.0.0